Reducing interns’ duty hours is problematic, studies show

BMJ 2013; 346 doi: (Published 26 March 2013) Cite this as: BMJ 2013;346:f1998
  1. Bob Roehr
  1. 1Washington, DC

Reducing interns’ hours on duty has disrupted training, had a minimal effect on their amount of sleep, and resulted in an increase in self reported medical errors, conclude two studies published in JAMA Internal Medicine.

Concern over the effect of long hours of duty on interns and their patients led the Accreditation Council for Graduate Medical Education to promulgate new rules for residency programs in the United States that took effect in July 2011. A central feature was limiting the maximum shift length to 16 hours, where previously 30 hour shifts were common.

The larger study was a survey, conducted over several years before and after the change, of interns at 51 residency programs at 10 university based and four community based training programs as part of the longitudinal Intern Health Study. The response rate was 58% of eligible interns (2323 of 4005).1

It found that reported duty hours fell from an average of 67 to 64.3 a week with the change in work schedule. The changes in sleep hours (from 6.8 to 7), depressive symptoms (from a score of 5.8 to 5.7), and wellbeing score (from 48.5 to 48.4) were not statistically significant.

More importantly, it found that “the percentage of interns who reported concern about making a serious medical error increased from 19.9% to 23.3% (P=0.007).”

“That’s a 15% to 20% increase in [concern about] errors—a pretty dramatic uptick, especially when you consider that part of the reason these work-hour rules were put into place was to reduce errors,” said the study’s lead author, Srijan Sen, a researcher at the University of Michigan Perelman School of Medicine.

He believes that the increase in concern about errors may reflect the greater number of patient handoffs between physicians that result from interns’ shorter work shifts. Previous studies have shown an association between the number of patient handoffs and a higher rate of medical errors.

While the number of hours worked by interns may have decreased officially, the workload has not, because hospitals have not hired additional staff. Sen said it was possible that interns were clocking out to comply with the mandatory limit on working hours but were continuing to complete administrative work off the clock.

He said that although the study did not collect such data, “anecdotally, some interns have reported working off the clock to complete their charting, both in the hospital and remotely from their homes.”

The second study involved four medical house staff teams (43 interns) at Johns Hopkins Hospital.2 It used a three month crossover design in which the residents worked shifts designed to pre- and post-2011 standards. Although the shorter work schedule did result in more sleep for interns, it had no effect on most other measures.

The number of patients admitted each month per intern fell from 24.8 to 16.5. “The minimal number of handoffs between interns increased from 3 to as high as 9,” the authors wrote, and the number of different interns caring for a patient over a three day stay rose from three to as high as five.

There also was a 25% reduction in opportunities to attend daily noon conferences. Interns, nurses, and training physicians all expressed dissatisfaction with the shortened work schedule.

The authors suggested that the Accreditation Council allow greater flexibility to institutions in testing models of residency education that might better meet their individual needs.


Cite this as: BMJ 2013;346:f1998